Ferromagnetic Soft Continuum Guidewire for Neurovascular Steering
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Solution Overview
Problem
Current robotic devices are unable to navigate the small and tortuous vascular structures in the brain due to miniaturization challenges and lack of appropriate technologies, limiting their application in cerebrovascular and endovascular neurosurgery.
Innovation Solution
A submillimeter-scale ferromagnetic soft continuum robotic device with an elongate body composed of soft polymer matrices and dispersed hard-magnetic microparticles, equipped with an inner core for support and potential optical fiber functionalities, allows for active omnidirectional steering via magnetic actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional robotic catheters with rigid magnets are miniaturized, then the device size is reduced, but the magnets become too weak to provide adequate deflection and steering control
Solution Approach 1:
The patent employs a composite structure consisting of a soft polymer matrix (e.g., PDMS, silicone rubber) embedded with ferromagnetic microparticles (e.g., iron oxide, magnetite). This composite material provides both the flexibility needed for miniaturization and the magnetic responsiveness required for steering. The ferromagnetic particles are distributed throughout the polymer matrix, creating a material that is both mechanically compliant and magnetically active, thereby resolving the contradiction between small size and adequate magnetic deflection capability.
Solution Approach 2:
The patent changes the magnetic properties of the device by incorporating ferromagnetic microparticles with specific magnetic moments and concentrations. By adjusting the concentration, size, and magnetic properties of the embedded particles, the device achieves sufficient magnetic deflection capability at submillimeter scales. The polymer matrix provides mechanical support while the ferromagnetic particles provide the necessary magnetic response to external fields, enabling effective steering despite the reduced device size.
2Ease of operation
If passive guidewires with pre-shaped tips are used, then the device can navigate tortuous paths, but multiple reshaping maneuvers are required and control becomes ineffective in highly tortuous paths due to friction
Solution Approach 1:
The patent replaces the mechanical twisting-based steering mechanism of conventional guidewires with a magnetic field-based actuation system. External magnetic fields are applied to the ferromagnetic microparticles embedded in the device, causing the device to deflect and change shape in response to the magnetic forces. This substitution eliminates the need for manual reshaping maneuvers and allows for continuous, precise control of the device shape and position, even in highly tortuous vascular paths where friction would otherwise prevent effective mechanical steering.
3Volume of moving object
If continuum robots are miniaturized to submillimeter scale, then they can access microvascular structures, but conventional actuation mechanisms become infeasible
Solution Approach 1:
The patent replaces conventional mechanical actuation mechanisms (such as shape memory alloys, piezoelectric actuators, or tendon-driven systems) with a magnetic field-based actuation system. The ferromagnetic microparticles embedded in the soft polymer matrix respond directly to external magnetic fields, enabling actuation without complex mechanical components. This approach is particularly suitable for submillimeter-scale devices where mechanical actuation mechanisms would be too large, complex, or difficult to manufacture. The magnetic actuation system can be implemented with simple external magnets or electromagnetic coils, making the device both manufacturable and controllable at the required scale.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device enables minimally invasive procedures in the microvascular system by providing precise navigation and control through complex and constrained environments, overcoming the limitations of existing technologies.
Implementation Method 1
an elongate body (generally in the form of a guidewire) composed of soft polymer matrices with dispersed hard-magnetic microparticles... capable of navigating the considerably smaller and more tortuous vascular structures... based on magnetic actuation
Data Source
Figure 1A~1D
Figure 2A~2D
Figure 2E~2J
AI summary
Robotic devices and methods for performing minimally invasive procedures on the vascular system, particularly cerebrovascular and endovascular neurosurgical procedures, where a submillimeter-scale continuum robotic device is configured and adapted for active steering and navigation based on external magnetic actuation. The submillimeter-scale continuum robotic device includes an elongate body having an inner core and an outer shell, where the outer shell is fabricated of an elastomeric material having a plurality of ferromagnetic particles dispersed therein.